Route container host-gateway to loopback on Windows

[Badbird5907]

The container egress listener binds to the address returned by gatewayForPlatform. On macOS it returns none (falls back to loopback) because Docker Desktop routes the host-gateway through a VM; every other platform got the Docker bridge gateway IP. On Windows the bridge IP is not a local interface on the host, so the bind fails and container start() aborts. Windows Docker Desktop behaves like macOS, so include _WIN32 in the loopback branch.

This is to add support for local container dev on windows machines. (cloudflare/workers-sdk#14566)

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[Badbird5907]

I have read the CLA Document and I hereby sign the CLA

[Badbird5907]

Hey, any updates on getting this merged?

[codspeed-hq]

Merging this PR will regress 1 benchmark

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 70 untouched benchmarks
⏩ 129 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	request[RegExpBenchmark]	4.1 ms	4.5 ms	-8.79%
⚡	simpleStringBody[Response]	23.4 µs	20.8 µs	+12.42%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing Badbird5907:windows-container-gateway (5b344d5) with main (97a94ed)}

Footnotes

1. 129 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩